Phase equilibria and thermodynamic assessment of the Mo–Nb-Re ternary system

Shao yu Yen, Shu chang Wu, M. Anshar Makhraja, Kai chi Lo, An chou Yeh, Kyosuke Yoshimi, Chuan Zhang, Shih kang Lin

Research output: Contribution to journalArticle

Abstract

Refractory elements are usually alloyed in the next-generation superalloys for better high-temperature stability and mechanical properties in the applications ranging from power plants to turbine blades in jet engines. Phase diagrams and thermodynamic models are the essential information for alloy design. Herein, the phase equilibria of the Mo–Nb-Re ternary system was investigated using the complementary methods including ab initio calculations at 0K, high-temperature experiments, and CALPHAD thermodynamic modeling. The ground-state formation enthalpy of the bcc, hcp, σ, and χ phases were determined. The as-cast Mo–Nb-Re alloy and those equilibrated at high temperatures (1973, 2173, and 2373K) were experimentally examined. With the ab initio energetics and high-temperature phase equilibria, the thermodynamic description (functions of Gibbs free energy) of the Mo–Nb-Re ternary system and subsystems was assessed or reassessed, which provides the foundation for further developments of superalloys.

Original languageEnglish
Article number101797
JournalCalphad: Computer Coupling of Phase Diagrams and Thermochemistry
Volume70
DOIs
Publication statusPublished - 2020 Sep

Keywords

  • Ab initio calculations
  • CALPHAD
  • Phase diagram
  • Superalloys
  • Thermodynamic assessment
  • Ultrahigh-temperature phase equilibria experiments

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Computer Science Applications

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